Essentially, the present invention comprises an improvement over or carrying forward of the invention set forth in applicant's prior U.S. Pat. No. 4,009,741, dated Mar. 1, 1977. Details of the improvements of the present invention over said prior patent are set forth hereinbelow:
The prior patent primarily comprises sets of opposed saws spaced transversely along parallel arbors respectively disposed above and below a path along which cants are moved to and beyond said sets of blades for purposes of simultaneously sawing said cants into a plurality of boards or other similar wood products and the edges of the boards also were formed selectively to provide plurality of different configurations, such as shiplap, tongue and groove, overlapping siding, and the like. Opposite surfaces or faces of the boards that were otherwise produced by by the machine actually were sawed faces and as such, contained saw marks and the like, as distinguished from planed finished surfaces.
Planed surfaces can be produced by certain types of saw blades having radially disposed planing members, either of an interrupted or continuous edge, and operable upon one or opposite faces of a saw blade. Illustrative of prior devices of this type in which the blades comprise both sawing and planing characteristics are prior U.S. Pat. No. 3,730,038 to Farb, dated May 1, 1973, U.S. Pat. No. 3,700,016 to Strobel, dated Oct. 24, 1972, and Canadian Pat. No. 964,557 to Weye, dated Mar. 18, 1975.
If blades of such prior patents are operated in pairs in the manner illustrated in applicant's prior U.S. Pat. No. 4,009,741, it has been found that particularly on the opposite faces of the product lumber either ridges or grooves usually are formed due to the inability of the planing or saw blades operating precisely in a common plane. Usually there is at least a minor offset so that a longitudinal groove or ridge is formed midway of said opposite faces of the product. As a result, it is necessary to pass such opposite faces through a planing machine. Further, in the event rounded corners are desired on the completed pieces, still further planing operations are necessary to form such rounded corners. Therefore, at present, it is common practice to form completed dimensional lumber, such as 2.times.4's, 2.times.6's, 2.times.8's and the like, by sawing the same from a cant and then planing the opposite faces and opposite edges as separate operations in a planing mill.
The purpose of the present invention is to eliminate the need for additional planing operations and form completely finished dimensional lumber items by a single pass through a sawing and planing machine, such as that of the present invenetion which is an improvement over applicant's aforementioned prior U.S. Pat. No. 4,009,741, details of which are set forth below: